Will Iran use or support Lebanon?

Ahmadinejad receives a hero's welcome from some in Beirut while others in the divided country are concerned.

Mahmoud Ahmadinejad, Iran's president, is in Lebanon for his first official state visit. And although he arrived in Beirut to a raptuous welcome, not everybody is happy.

The US and Israel have already expressed concerns that the visit could bolster support for Hezbollah.

Ahmedinejad met his Lebanese counterpart - before he sits down with Hassan Nasrallah, the Hezbollah leader, and tours the movement's southern stronghold.

But why is he visiting now? Is it a visit to express support to Lebanon or a celebration of rising influence there? And why is the West so concerned?

Joining the programme are Seyed Mohammad Marandi, the head of North American Studies at the University of Tehran, Alistair Crooke, the director of the Conflicts Forum, and Andrew Tabler, a fellow at the Washington Institute for Near East Policy.